High pitched whine/squeal vr6

[matt59876 0]

Recently I've had a bit of a rough idle and its tried to stall on me a couple of times so this evening I thought I'd give the isv, throttle body and intake elbow a clean (coil, leads and plugs were replaced less than 10k ago so I'd ruled these out as a cause for the rough idle). Now it is all back together I started it up and after a few minutes the idle settled nicely. I went for a short drive to see the difference made and it runs really well but when I got back home a high pitched noise was coming from the engine, it seems to be coming from the throttle body but I'm not certain as there's a few things in that area. Does anybody have any ideas what the noise could be?

[seanl82 23]

Auxiliary belt or tensioner would be my guess. Kind of below the Throttle Body I suppose.......... but the tensioner is often past its best. Easy to change the bearing though and dirt cheap which is good.

Put your finger on the tensioner with the engine running, or do the extension bar test for a better idea. Both will give you a pretty good indication if the bearing is screwed. Mine started getting noisy and got progressively worse over literally a couple of weeks where I replaced it, and when I got it off it was really stiff and the pulley barely turned by hand!

Edited March 11, 2014 by seanl82

[VW_OwneR_85 2]

could be the belt tensioner pully bearing although that wouldn't explain rough running, if you thread an M8 bolt into the belt tensioner {you will see a threaded hole for this} this will slowly release the tension of the belt and you can then remove the belt from the engine just take note of the routing of the belt, run the engine for like 10 seconds and see if the noise is still there, don't run it for long as the water pump wont be working! also spin the water pump by hand see if it feels rough, same with alternator

 

 

lol didn't see your post sean ;)

[seanl82 23]

could be the belt tensioner pully bearing although that wouldn't explain rough running, if you thread an M8 bolt into the belt tensioner {you will see a threaded hole for this} this will slowly release the tension of the belt and you can then remove the belt from the engine just take note of the routing of the belt, run the engine for like 10 seconds and see if the noise is still there, don't run it for long as the water pump wont be working! also spin the water pump by hand see if it feels rough, same with alternator

 

 

lol didn't see your post sean ;)

 

 

 

Great minds and all that.

[matt59876 0]

Thanks guys, I'll give that a try tomorrow. I hadn't thought of that as I haven't touched it and the noise sounds electronic (if that makes sense?) but I guess it could be dry bearings.

 

I forgot to say in my original post that when I turn off the engine the noise fades to silence after a second or so. Does this sound like the aux belt/tensioner?

[Purple Tom 0]

Sounds more like an air leak or vacuum leak, particularly if it's combined with a rough idle. What engine management is the car running - coilpack/dizzy? OBD1 or OBD2?

[matt59876 0]

It's coil pack obd1 with a schrick manifold. The idle is pretty much perfect now though-fixed one problem and created another it seems.

[sankysvr6 0]

Are you sure the whine is not coming from the auxiliary water pump? as that's near the throttle body.

 

Is the whine still there after you have switched of the engine, for around 10 to 15 mins?

[matt59876 0]

I've not checked the water pump yet. It only continues for a second or so and fades to silence.

[sankysvr6 0]

If you switch the ignition on, you don't have to start the car and feel the aux water pump. You should feel it humming away like a good one.

 

Once you switch off feel it again it should carry on humming for awhile.

[matt59876 0]

Fixed it this weekend. It was air leaking. I had put one the schrick gaskets back on the wrong way round. It must have been a small gap to make such a noise but all fixed now :-)